package org.linlinjava.litemall.core.util;

/**
 * @author Administrator
 * @since 2020/3/7 21:05
 */
public class DistanceUtil {

    private static double EARTH_RADIUS = 6378.137;

    private static double rad(double d) {
        return d * Math.PI / 180.0;
    }

    /**
     * 通过经纬度获取距离(单位：米)
     *
     * @param lat1 经度1
     * @param lng1 纬度1
     * @param lat2 经度2
     * @param lng2 纬度2
     * @return
     */
    public static int getDistance(double lat1, double lng1, double lat2, double lng2) {
        double radLat1 = rad(lat1);
        double radLat2 = rad(lat2);

        double a = radLat1 - radLat2;
        double b = rad(lng1) - rad(lng2);

        double s = 2 * Math.asin(Math.sqrt(Math.pow(Math.sin(a / 2), 2)
                + Math.cos(radLat1) * Math.cos(radLat2)
                * Math.pow(Math.sin(b / 2), 2)));
        s = s * EARTH_RADIUS;
        s = Math.round(s * 10000d) / 10000d;
        return (int) (s * 1000);
    }

    public static void main(String[] args) {
        int distance = DistanceUtil.getDistance(35.953739, 120.203362, 35.953839, 120.208362);
        System.out.println(distance);
    }
}
